Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 242355
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
755 PM EDT SUN MAY 24 2015

.SYNOPSIS...
ISSUED AT 755 PM EDT SUN MAY 24 2015

PRIMARILY PARTLY CLOUDY SKIES AND WARM CONDITIONS ARE EXPECTED
OVERNIGHT. CONDITIONS WILL BE MAINLY DRY...HOWEVER A SMALL CHANCE
FOR A SHOWER EXISTS ACROSS NORTHWEST INDIANA AND EXTREME
SOUTHWEST LOWER MICHIGAN TOWARD DAYBREAK. A FEW MORE SHOWERS AND
STORMS ARE POSSIBLE MONDAY AND AGAIN LATER THIS WEEK ACROSS THE
AREA...WITH CONTINUED WARM CONDITIONS THROUGH THE WEEK.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 350 PM EDT SUN MAY 24 2015

MAIN CHALLENGE FOR SHORT TERM PERIOD IS PRECIP POTENTIAL TONIGHT
AND MONDAY.

AMPLIFIED EASTERN CONUS RIDGING WILL CONTINUE THROUGH MEMORIAL
DAY. SHARP S/W WILL EJECT NORTHEASTWARD OUT OF BROAD WESTERN
CONUS TROF LATE TONIGHT TOWARDS THE WESTERN GREAT LAKES ON
MONDAY. STRENGTHENING LOW LEVEL JET WILL ADVECT INTO THE REGION
TONIGHT...AND THROUGH THE REGION MONDAY MORNING. THIS WILL BE A
FOCUS FOR PRECIPITATION POTENTIAL LATE TONIGHT INTO MONDAY
AFTERNOON.

THIS AFTERNOON INTO EVENING...EXPECT MOST AREAS TO REMAIN
DRY...HOWEVER KEPT A SLIGHT CHANCE POPS ACROSS FAR NW...AS HI RES
GUIDANCE SUGGESTS ISOLATED SHOWER/T-STORM DEVELOPMENT TOWARD 00Z
TONIGHT. MAINLY DRY CONDITIONS ANTICIPATED THROUGH MUCH OF THE
OVERNIGHT W/ RIDGING HOLDING ACROSS THE REGION. NO MAJOR CHANGES
TO LOW TEMPS OVERNIGHT.

KEPT POPS IN THE CHANCE RANGE TOMORROW AS SIGNS POINT AGAINST
MORE WIDESPREAD PRECIPITATION POTENTIAL. MID/UPPER FORCING WILL
REMAIN WEST/NW OF THE REGION LATE TONIGHT THROUGH TOMORROW.
ALTHOUGH 925-700MB MOISTURE SLOWLY INCREASES OVER THE NEXT 12-18
HOURS...MASSIVE DRY SLOT AT 700MB AND ABOVE WILL ROTATE THROUGH
THE REGION WITH S/W PASSAGE. SLIGHT EML ADVECTION W/ WARM
NOSE/CAPPING CENTERED BETWEEN 700-600MB PER MODEL SOUNDINGS
SHOULD KEEP SHOWERS/CONVECTION MORE ISOLATED TO SCATTERED RATHER
THAN WIDESPREAD. ONCE THIS MIXES OUT LATER IN THE AFTERNOON...LOW
LVL JET AND UPPER FORCING WILL HAVE EXITED THE REGION...AND MIXED
BOUNDARY LAYER WILL BE RATHER DRY. FOR WX TYPE...KEPT THUNDER OUT
OF THE FCST UNTIL AFTER 15Z...WITH JUST A SLIGHT CHANCE OF
THUNDER FROM 15Z THROUGH 18Z. POPS RAMP DOWN SIGNIFICANTLY FROM
WEST TO EAST AFTER 18Z WITH DRY SLOT ROTATING THROUGH. KEPT
TEMPERATURES SIMILAR TO PREVIOUS FCST.

&&

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 PM EDT SUN MAY 24 2015

PIECEMEAL EJECTION OF LARGE WESTERN CONUS TROUGH WILL BRING
PERIODIC CHANCES OF RAIN THROUGH WEDNESDAY GIVEN MOIST AND
MODESTLY UNSTABLE ENVIRONMENT IN PLACE. BEST CHANCES OF RAIN WILL
LIKELY BE LATE IN THE DAY ON TUESDAY WHEN MOST OF THE LATEST
GUIDANCE SUGGEST A MORE FORMIDABLE SHORTWAVE VORT WAX WILL LIFT
THROUGH THE GREAT LAKES. LLJ AND ASSOCIATED MOISTURE TRANSPORT
INCREASE AHEAD OF THIS WAVE AND DECENT MIDLEVEL CVA/HEIGHT FALLS
SHOULD PROVIDE ADEQUATE FOCUS FOR SCT-NUM SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN OUR NORTHWEST. FAVORABLE DIURNAL
TIMING WILL ALSO ALLOW THIS WAVE TO CAPITALIZE ON SOME MARGINAL
INSTABILITY. GIVEN THESE FACTORS AND RELATIVELY GOOD AGREEMENT IN
12Z MODEL SUITE...WENT AHEAD AND BUMPED AFTERNOON POPS INTO
LIKELY CATEGORY. SEVERE WEATHER RISK APPEARS LOW. 0-6 KM BULK
SHEAR VALUES WILL BE IN THE 25-30 KT RANGE BUT PALTRY MIDLEVEL
LAPSE RATES OF 6 C/KM OR LESS ONLY GENERATE AROUND 500 J/KG OF
0-1KM MLCAPE DESPITE SURFACE DEWPOINTS IN THE MID TO UPPER 60S. A
FEW STRONG STORMS MAY BE POSSIBLE IF WE CAN GET A LITTLE BETTER
SURFACE HEATING AND/OR MOISTURE POOLING BUT CHANCES OF WIDESPREAD
SEVERE WEATHER APPEAR LOW AT THIS POINT.

CHANCES FOR CONVECTION WILL THEN CONTINUE INTO WEDNESDAY BEFORE
SHORTWAVE RIDGING LEADS TO A MORE SUSTAINED PUSH OF SUBSIDENCE
AND NEGATIVE THETA-E ADVECTION. DECENT PUSH OF LOW LEVEL
CONVERGENCE ALONG FRONTAL BOUNDARY BUT MOST OF THE BETTER
MOISTURE WILL BE STRIPPED AWAY BY THIS POINT. HELD WITH JUST HIGH
CHANCE POPS FOR NOW. MARGINAL SHEAR/INSTABILITY SUGGEST ANOTHER
LOW...BUT NOT ZERO...CHANCE FOR SEVERE WEATHER. AFTER A BRIEF
BREAK ON THURSDAY...CHANCES FOR RAIN RETURN FOR FRIDAY AND THE
WEEKEND AS A TROUGH PASSING THROUGH ONTARIO SENDS A WEAK FRONT
INTO THE REGION. POTENTIAL EXISTS FOR THIS FRONT TO STALL
SOMEWHERE OVER THE OHIO VALLEY BUT DETAILS HIGHLY VARIABLE AT
THIS POINT AND WILL HOLD WITH JUST BLANKET CHANCE POPS. ABOVE
AVERAGE TEMPS WILL EVENTUALLY SETTLE LOWER ONCE THIS BOUNDARY
PASSES BUT EXACT TIMING OF THIS TRANSITION IS UNCERTAIN AND STAYED
CLOSE TO INITIALIZED CONSENSUS BLEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 755 PM EDT SUN MAY 24 2015

PRIMARILY VFR CONDITIONS EXPECTED THROUGH THE TAF PD. CONTD
CONCERN WITH RESPECT TO LOW LEVEL WIND SHEAR LATER OVERNIGHT AS
DECOUPLED LOW LEVEL SSWRLY JET RAMPS TO 45-50KTS. TIMING OF PSBL
HIGH END MVFR CIGS AND SMALL CHC SHRA MON AM INVOF KSBN
ASSOCIATED WITH TIMING OF SHORTWAVE ENERGY CURRENTLY ACRS SRN MO
LIFTING NNEWD INTO NERN IL WARRANT ONLY VCSH MENTION ATTM. MEAGER
MID LEVEL LAPSE RATES ACRS NRN IN PRECLUDE NEED FOR MENTION OF
ANY FURTHER CONVECTIVE ACTIVITY THROUGH REMAINDER OF THE PD.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...BEACH HAZARDS STATEMENT FROM MONDAY MORNING THROUGH MONDAY
     EVENING FOR MIZ077.
OH...NONE.
LM...GALE WARNING FROM 10 AM TO 4 PM EDT MONDAY FOR LMZ043-046.

&&

$$

SYNOPSIS...MURPHY
SHORT TERM...NG
LONG TERM...AGD
AVIATION...MURPHY

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